Process of curing lumber.



' E, n. SIBMAN.

PROCESS OF CURING LUMBER.

APPLICATIOR-FILED MAR. 3, 1914.

1,199,120 PatentedSept. 26,1916.

WITNESSES IN VENTOR EDVIARD D. SIDMAN, OF ROCHESTER, NEW YORK, AS SIGNOR TO THE SIDMAN COMPANY,

OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

PROCESS OF CURING LUMBER.

Application filed March 3, 1914.

ToaZZ whom it 121 ag concern Be it known that I, EDWARD D. SIDMAN, a citizen of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Processes for Curing Lumber, of which the following is a specification, reference being had therein to the accompanying drawings.

This application is a continuation in part of my application Serial No. 373,349, filed May 18, 1907.

The invention relates to process for the curing of lumber and has for its object the removal from the pores of the wood of the sap and other substances which are detrimental.

The invention comprises essentially the subjecting of the lumber to a humid atmosphere, which opens the pores and fills the same with moisture, dissolving the solid impurities, and the further treatment to increase the temperature while maintaining practically the same degree of humidity. Thus the detrimental substances are first dissolved and then partially forced out by expansion, after which the lumber may be dried.

A specific application of my process in the treatment of lumber is as follows: The green lumber is first placed in a kiln or other closure as nearly air tight as possible, and is exposed therein to an atmosphere at a temperature from tut-)0 F. and a humidity of from 80 to 95, as measured by the hygrometer. ,This condition is maintained for a period of time varying according to the thickness of the lumber and other conditions, from thirty minutes to eight hours being sufiicient to thoroughly permeate the pores with the moist atmosphere.

In the second step of the process the heat is increased as rapidly as possible to a temperature of 165 F. or over, while practically the same degree of humidity, preferably 95 by hygrometer, is maintained, and this is continued from twelve to forty-eight hours, and has the effect of expelling a percentage of the impi ities by expansion. For instance, in the case of oak lumber, the tannic acid and sap are thus expelled.

The third step of the process is the changing of the atmosphere enveloping the material by proper ventilation while still maintaining a temperature not under 165 F.

Specification of Letters Patent.

Patented Sept. 26, 191 6.

Serial No. 822,169.

and preferably over 165. During this treatment the eliminated impuritiesare carried away and the humidity of the atmosphere gradually decreases, but never to a point under 30. The time of the treatment may vary according to the condition and nature of the lumber from one to ten days, or more according to the kinds of lumber.

Lumber subjected to the treatment above described is left in a softer and yet stronger condition than when dried in the ordinary manner and will not warp, check, or expand and contract under various atmospheric changes, as is the case where the impurities have not been removed but are dried in.

Any suitable form of apparatus may be employed for carrying out my process, but, as shown in the figure,I have illustrated diagrammatically a kiln having two compartments A and B which are provided with lieataadiating steam )ipes C and spray pipes D, and with ventilators E in the compartment B. The first two steps of the treatment are carried on in the compartment A, after which the lumber or other material is transferred to the compartment B, in which it remains during the final drying treatment. However, if desired, the whole processmay be carried out in one suitably equipped chamber.

\Vhat I claim as my invention is 1. The method of curing lumber, which comprises subjecting it to a humid atmosphere at relatively low temperature until the moisture penetrates through the wood and dissolves the detrimental substances therein, and then increasing the temperature while maintaining practically the same degree of humidity as that of the atmosphere to which the lumber is originally subjected to expel said detrimental substances by expansion.

2. The method of curing lumber, which comprises exposing it to an atmosphere high in humidity and relatively low in temperature until the moisture penetrates through the wood and dissolves the detrimental substances therein, and then increasing the temperature while maintaining practically the same degree of humidity as that to which the lumber is originally exposed and continuing this treatment until the detrimental substances are partially expelled by expansion, and finally drying by maintaining the high temperature and gradually decreasing the humidity, by ventilation.

3. The method of curing lumber, which comprises subjecting the green lumber to an atmosphere at a temperature from to F. and of a humidity from 80 to and continuing the treatment until the moisture penetrates through the wood and the detrimental substances contained there-- in are dissolved, in then increasing the teen 'perature to approximately F. While substantially the same degree of humidity is maintained and continuing this treatment until the detrimental substances are partially e peiled by expansiun. and in then maintaining the high temperature and gradually decreasing the humidity by ventilm tinn to eti'ect the drying.

in testimony whereof i aiiix my signature in presence of two Witnesses.

EDWARD D. SIDMAN.

Vitnesses JAMES P. BARRY, PHYLLIS COBL'RN. 

